Means for indicating defects in thread



E. A. KEELER May 20, 1941.

MEANS FOR INDICATING DEFECTS IN THREAD Filed March 31, 1938 2Sheets-Sheet 2 l a/ues No/ofi- Genera/01' Se) FIG. 5.

INVENTOR. EARL A. KEELER ATTORNEY.

Patented May 20,

* UNITED STATES PATENT OFFI MEANS FOR INDICATING DEFECTS IN THREAD IEarl A. Keeler, Norristown, Pa., assignor to The Brown InstrumentCompany, Philadelphia, Pa., a corporation of Pennsylvania ApplicationMarch 31, 1938, Serial No. 199,119

6 Claims.

This invention relates to the detection of defective filaments in athread and more particularly to'improved apparatus therefor.

A general object of the invention is to provide simple, reliable, andefiicient means for registering the presence of defective filaments in athread.

A specific object of the invention is to provide improved apparatus fordetecting and registering the presence of defective filaments in athread comprising a delicate switch mechanism adapted to be actuatedwhen engaged by defective filaments and a relay mechanism associatedtherewith adapted to quickly effect a recording operation responsivelyto such actuation of the switch mechanism. r

A further specific object ofthe invention is to provide apparatus of thecharacter above described in which the relay mechanism referred to iscapable of quickly resetting itself so as to be ',in operative conditionin a minimum of time for recording the next engagement of defectivefilamentswith the switch mechanism after just having e flected such arecording operation.

A still further specific object of the invention is to provide simpleand efiicient means for detecting the presence of defective filaments ina plurality of threads simultaneously together with means actuatedthereby for recording the imperfections in all thethreads on a singlerecording means, and for visibly indicating the imperfections in thethreads by means individual to each of the threads.

In the manufacture of fabrics from rayon or other threads, the presenceof defective filaments in the individual threads shows up in thefinished material in the form of fuzzy ends- Heretofore, in order toeliminate these fuzzy ends, provisions have been made for the inspectionby observation of'aportion of the thread during transfer of the threadfrom spool to spool and rejection of any spools having an excessivenumber of defective filaments This inspection operation is obviouslyexpensive, and, more important from the standpoint of producing qualitymaterial, is in-;

selves are extremely fine and small in diameter,

are made up from 40 to or more of such filaments. In accordance with apreferred embodiment of my present invention, I provide means for suchautomatic detection including a delicate switch member arranged in thepath of the thread and an associated sensitive trigger device undercontrol of said switch mechanism. When defective filaments engage thedelicate switch mechanism, which has little inertia, a contact is closedthrough which only a current of minute magnitude flows, but which iseffective to operate the trigger devicereferred to and thereby controlthe passage of a relatively'larger current.

A novel solenoid and plunger arrangement connected in circuit with thetrigger device is actuated when the latter is energized and operates torecord the thread imperfection on a recorder chart and simultaneouslyoperates to deenergize the trigger device. This, in effect, permits theduration of engagement between the delicate switch mechanism and thedefective filament to be extremely short and yet a record of the threadimperfection will be had. Simultaneously with the recording operation,the instrument is restored to its original condition and is immedi atelyeffective to record the next thread imperfection that engages thedetector mechanism.

The various features-of novelty which characterize my invention. arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,however, its advantages and specific objectsattained with its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described a preferred embodiment,of theinvention.

Of the drawings:

Fig. l is a more or less diagrammatical view illustrating one form ofthe invention;

Figs. 2 and 3 illustrate in detail a preferred form of detector switchmechanism which may be Fig. is a wiring diagram showing the circuitconnections of a portion of the arrangement of Fig. 4.

As illustrated, more or less diagrammatically in Fig. 1, provision ismade for arranging. a detector i in the path of a moving thread 2 fordetecting defective filaments in the latter. For clarity anddefiniteness of illustration I have shown my invention as adapted foruse with a winding machine in which the thread is unwound from a cop 3and rewound on a cone 3a, the latter being mounted for rotation anddriven at a desirably high speed by means not'shown. As the thread 2unwinds from the cop 3 it passes through suitably spaced guide members 4to a tension adjusting device 5 which may be of any suitable type knownto those skilled in the art. After passing through the device 5, thethread passes over guide rolls 6 and through a guide carried on theend'of a winding arm 7. Winding arm I is in cooperative relation withthe cone 3a and is continuously moved back and forth along the length ofthe latter by means not shown so that the thread 2 is wound on the cone3a with a criss cross or helical wind. The thread guides 4 and thetension adjusting device 5 are mounted on a suitable bracket 8, whichmay in reality.

comprise part of the Winding machine itself, and the cop 3 is shown assupported by the base member of the bracket.

The detector unit I, which will be described more in detail hereinafterin connection with Figs. 2 and 3, includes a contacting arm 9 havtheposition of Fig. 1 out of engagement with contact l3 due to the actionof a pair of fixed flexible fingers l5 and I6, carried by stationarymembers Ma and Nb also mounted on the member B. Fingers I 5 and I6engage arm 9 on either side so that as defective filaments strike thestirrup l2 and rotate arm 9 into engagement with the flexible contactl3, the flexible finger l5 sets up a resisting force which tends torestore arm 9 to its normal position when the defective filaments havepassed on. Oscillation of arm 9 is dampened out as a result of thecombined action of fiexible fingers l5 and I6 for, if arm 9 tends tomove past its normal position on being returned thereto by finger l5,finger l6 exerts a restraining force on the arm and reduces [the extentof such movement whereby arm 9 quickly ing one end disposed in the pathof the thread and pivoted intermediate its ends for rotation on a lightsuspension cord l9 which may be of silk or any other suitable material.As best seen in Figs. 2 and 3, cord I0 is suspended between'oppositearms of a U-s'haped member ll. arm 9 is provided at its right hand endwith a bifurcated portion or stirrup 12 which may desirably be formed byproviding and bending a portion of the arm 9 itself into such shape.Stirrup I2 is so arranged with respect to the thread that a respectivearm is disposed on either side of the thread. The arms of the stirrupare separated by a distance slightlygreater than the ormal diameter ofrthe thread so as to permit leeway for thread whipping, or in otherwords jerky transverse movement of the thread, but are desirably closeenough to the sides of the thread so that any defective filaments on thelatter will engage one or the otheror both arms.

As illustrated inFigs. 2 and 3, the detector unit I is contained in acase A, which may be of metal or other suitable material,- and ismounted in any convenient manner on bracket 8 or any other convenientpart of the winding machine. A base B which may be of Bakelite or otherinsulating material, is fixedly secured to the inside of the case and isprovided for mount- Contact ing the U-shaped member II and the otherparts comes to rest in its normal position.-

Thread 2 is guided into the stirrup l2 by guide members I1 and I8rigidly secured to the case A by screws, as shown, and-having saddleportions at their upper ends for guiding the thread. In order tofacilitate the adjustment of the saddle portions relatively to thestirrup 12, the guide members are preferably provided .with slotsthrough which the screws holding the guide members to the case A pass sothat by loosening the screws the guide members may be adjusted to thedesired position and then rigidly secured in that position by tighteningthe screws. The saddle portions of guide members l1. and I8 have asuitably rounded edge, as shown, for guiding the thread whereby thelatter is normally maintained exactly between the arms of stirrup I2when the'gui'de members have been suitably adjusted. Because of theconstant sliding of the thread on the guideimembe'rs, it is noted, thesaddle portions will be quickly worn away and rendered ineffective formaintaining the thread intermediate the arms of stirrup I2 unless thesaddle portions are suitably hard and wear resisting. Guide members I!and I8 may'be composed of various substances which are suitably 'wearresisting such, for'example, as solid porceprefer to-employ guidemembers I! and I8 composed of nitralloy with a nitrided case. I

It is noted the resiliency of contact I3 permits movement ofcontactingarm 9 to any position -within limits which may be takenby thelatter.

This feature is important in that injury to the thread or detector isprevented in the event that a knot or other unusually largeprojection-on the thread engages the stirrup l2.

When the contacting arm 9 is rotated into engagement with the flexiblecontact l3, a circuit including the contacts will be completed whichoperates to control the potential of thecontrol grid ill of anelectronic valve l9 which.

may desirably be a gaseous discharge valve, for example, an R. C. A.type 885. Valve l9 includes an anode 29, the control grid 2|, a cathode22, and a heater filament 2,3. Energizing voltage is supplied filament23 from the secondary winding 24 of a transformer 25 having a primarywinding 26 connected to the alternating voltage supply conductors L andL' In the operation of the electronic valve IS, a threshold discharge isinitiated between the con- 4 ber 48, but is actuated in anupward trolgrid 2| and cathode 22 when the grid potential relative to the cathodepotential attains a predetermined value, depending upon the Criticalgrid-to-cathode voltage characteristic of the valve. The cathode-to-gridthreshold discharge, when once initiated, is self supporting and ifsufiicient voltage exists between the anode 28 and the grid 2| the saidthreshold discharge transfers to the anode, thus effecting a completecontinuous discharge between the anode 28 and the cathode 22. Thisdischarge continues to pass between the anode and cathode as long as thevoltage impressed therebetween does not decrease below the criticalbreak-off value for the valve. That is to say, the control grid 2| isthen ineffective in controlling the discharge between the anode andcathode 22, and the discharge can only be st pped by decreasing thevoltage between the anode and cathode to a value below the criticalbreak-off value.

In accordance with my present invention the I potential of the controlgrid 2| is controlled by the contact arm 9 and contact l3 together withother means-to be described for initiating a discharge between the anode28 and cathode 22, and the discharge that subsequently takes place isstopped by means responsive to that discharge which operates to reducethe voltage impressed between the anode and cathode below the criticalbreak-ofi value. 4

When contact arm 9 is out of engagement with flexible contact I3, anegative potential suificient to render the valve non-conductive ismaintained on the control grid 2| of valve l9, but when contact arm 9engages contact I3, a portion of the negative potential on the controlgrid 2| is shunted out whereby the valve is rendered conductive.

The means for maintaininga negative bias on the control grid-2| of valvel9 and Ear varying the magnitude of that bias on engagement of contactarm 9 and contact |3 includes a pair of batteries 21 and 28 and a fixedresistor 29. Eatteries 21 and 28 and resistor 29 are connected in aseries circuit between the cathode 22 of valve I9 and control grid 2|which may be traced from the cathode 22 to a conductor 38,;the positiveterminal of battery 21 and therethrough to the negative terminal, thepositive terminal of battery 28 and therethrough to the negativeterminal, resistor 29, and conductor 3| to the control grid 2| Contactl3 of the detector mechanism is connected by conductors 32 and 3| to thecontrol grid 2 I, and contact arm 9 is connected by a conductor 33 tothe point of engagement of batteries 21 and 28.

Thus, as will be clearly apparent, when contact arm 9 is out ofengagement with contact l3, the combined potentials of batteries 21 and28 will be maintained between cathode 22 and control grid 2|, but uponengagement of contact arm 9 and contact |3-, battery 28 will be shuntedout, and battery 21 only will be effective to negatively bias controlgrid 2|. Resistor 29 is provided to limit the value of currentdischarged by battery 28 to a low value when contact arm 9 and contactl3 are in engagement.

Anode voltage is supplied valve |9 from a battery 34 through a switchmechanism 35 comprising a fixed contact 38 and a flexible arm 31 whichare normally in engagement but are adapted .to be moved out ofengagement by a plunger 38 upon movement of the latter in an upwarddirection.

Plunger 38 comprises the core of a relay winding flexible spring mem- 39and normally rests on a direction when the relay winding is energizedand falls back upon the spring member 48 when the relay is deenergized.Flexible spring member 48 is arranged in cooperative relation with asuitable ribbon 42 and a recorder chart 43 for marking a dot on thechart each time the plunger 38 falls back thereon. A slight protrusionis formed in the spring member 48 for making a clearly defined dot onthe chart.

As illustrated,spn'ng member 40 is mounted on the lower end of a metalpost 4|] which is rigidly connected at its other end to one end of aninsulating rectangular block 38 of Bakelite or other suitable material.A cylindrical tube 39 which may desirably be of brass, is insertedthrough an opening in the other end of block 38 and is fittedsecurelysthereto. Spring member 31 and contact '36 are mounted on theupper surface of block 38 as shown. Relay winding 39 is wound on tube 39and plunger 38 is inserted in the tube 39 and is adapted to be guidedthereby. A brass rod 4|, which extends axially of the plunger and isrigidly connected with theupper end thereof, is desirably provided tomake it possible for the plunger to separate switch member 31 andcontact 38, when actuated, without leaving the province of winding 39.

The recorder chart 43 is adapted to be driven by a continuously rotatingroller 44 which may be driven in any convenient manner, as, for example,by a unidirectional electrical motor (not shown) so that anyimperfections in the thread ,will be recorded on the chart as a seriesof contiguous marks on a straight line.

Relay winding 39 is connected in the output circult of valve [9 inseries with the battery 34 andthe switch mechanism 35 so that when thevalve I9 is rendered conductive as a result of impact of defectivefilaments with the detector stirrup l2, energizing current fiows throughthe relay winding. Plunger 38 is then actuated in an upward directionand rod 4|, which is integral therewith, strikes the switch arm 31 andquickly moves the latter out of engagement with the contact 38 whereuponthe flow of anode current to valve I9 is interrupted and the plunger 38falls back and strikes the flexible spring 40 causing the latter to makea. mark on the recorder chart through the ribbon 42. L

It is noted that normally a very short contact period between thecontact arm 9 and the contact l3 of the detector mechanism results fromimpact of defective filaments on the stirrup l2 so that when plunger 38interrupts the anode circuit of valve I9, the latter remainsnon-conductive until the detector mechanism is again actuated by impactof defective filaments. In the interim, plunger 38 is held off therecorder chart 43 by the flexible spring member 48 in readiness for thenext marking operation It is noted that when an exceptionally bad defectstrikes the detector stirrup l2, the contact arm 9 may be held inengagement with the contact I3 for a longer period whereupon the plunger38 will be caused to make several closely spaced marks on the chart.

In Figs, 4 and 5 I have illustrated, more or less diagrammatically, amodification of my invention which may be employed for detecting thepresence of defective filaments in a plurality of threads simultaneouslyand for recording the thread imperfectionson a single recorder chart. Inthis form of my invention a motor-generator set 45 employing a motor 46energized from the alternating voltage supply conductors and a generator41 driven thereby is provided for supplying direct 4 t a es currentanode voltage to a plurality of valves l9 and a suitable rectifier unit56 is provided for supplying a suitable negative bias for the valvecontrol grids.

As illustrated in Fig. 4, a plurality of detector units i, la and lb areprovided and a plurality of switch mechanisms 35, a and 35b, each ofwhich includes an individual plunger 38in co operative relation with arecorder chart 43, are provided for recording the thread imperfectionsin the individual threads. The switch mechanisms 35 are mounted side byside in an instrument casing 48 of rectangular outline.

The casing 48 is formed with a doorway 49 at its front side, which isnormally closed by a door 50 connected at one side to the casing body byhinges 5i. The door 50 is'provided at its opposite side with a knob 52,and is ordinarily provided with a locking means including a keyhole inthe knob 52 for locking the door in its closed position. In addition tothe switch mechanisms 35, 35a and 35b,'casing 48. houses a recorderchart 43 and chart roll therefor which is driven by a continuouslyrunning unidirectional motor (not shown).

By virtue'of the fact that switch mechanisms 35,3511 and 35b are of thetype disclosed, a. relatively large number may be placed side by side ina narrow space whereby a compact unit is obtained. The systemillustrated in Figs. 4 and 5, for example, is of commercial form inwhich twenty-four such devices are employed side by side in a space lessthan eleven inches wide.

As illustrated, the detector units Lia, and lb are connected by a cableto the terminal posts of an instrument casing 53 which houses aplurality of electronic valves I9, I91: and H17 and in the case of theform above mentioned, it houses twenty-four such valves. As is shown indetail in Fig. 5, all of the detector contact arms 9, 9a and 9b areconnected .to'a common conductor 54 which is connected to a conductor 55common to all of the cathodes of the valves. It

is noted the common cathode conductor 55 and the metallic cases housingthe detector units may desirably be both connected to ground, for ex-'ample, to the winding machine frame 8, to ensure that engagement of thedetector arms 9, 9a or 9b with their metallic casings will not result inoperation of its associated recording mechanism, to thereby falselyindicate the presence of defective thread filaments.

In Fig. 5, in order to avoid confusion of the I drawings, I have shown acircuit for detecting the presence of defective filaments in only threethreads but it will be understood that defective filaments may bedetected in twenty-four or any additional number of threads, as desired,the, only limit as to the actual number being the load that the motorgenerator set 45 and the rectifier unit 56 can safely handle.

' In this arrangement, as mentioned hereinbefore, a suitable rectifierunit 56 energized from the alternating voltage supply conductors L and Lhas been provided for supplying negative bias to the ,control grids ofvalves I9, I91: and l9b in lieu of batteries 21 and 28 which areemployed in Fig. l for that purpose. The rectifier 56 includes anelectronic valve 51 which may be a conventional full Waverectifier,-having a pair of anodes 58 and 59 and a filament cathode 60connected by conductors 6| and B2 to the secondary winding 63 of atransformer 64. Transformer (it is a combination step-up and step-downtransformer and includes a high voltage secondary winding 55, and lowvoltage secondary windings 63 and 66, and a line voltage primary winding577 connected directly to the alternating voltage supply conductors Land L The anodes 58 and 5d of valve 51 are connected by conductors 68and 69 to the terminals of the transformer secondary winding 65, and therectified anode current of the valve is connected across the terminalsof a filtering condenser 70. A center tap on the secondary winding isconnected by a conductor M to one terminal of the condenser l0 and theother terminal of the latter is connected to the filament cathode 60 sothat a direct current voltage is maintained across the condenser 70. The

- positive terminal of the condenser .10 is con nected by a conductor T2to the conductor 55 which is common to all the cathodes of the valvesand the negative terminal of the condenser 10 is connected to each ofthe control grids thereof through a respective resistance 29, 29a, and29b.

As mentioned hereinbefore, the switch arms 9, 9a and 9b of theindividual detector mechanisms are connected to the common cathodeconductor 55. In addition each of the cooperating flexible contacts l3,l3a and [3b are connected to a respective valve control grid so thatupon engagement of a switch contact arm with its associated contact, thenegative bias on the corresponding control grid will be shunted out andthat valve accordingly will be rendered conductive; Actuation of aplunger 38, 38a or 38b associated with that valve as a result ofenergization of the particular relay winding connected in the anodecircuit of that valve operates to deenergize the valve and to record thethread imperfection immediately thereafter by marking a dot on therecorder chart 43. For facilitating scanning the chart, the latter maybe marked off into a number of divisions corresponding to the number ofdetector units being employed and each of the chartdivisions may benumbered to correspond with a detector unit so that imperfections ineach of the individual threads will be recorded in a division of thechart numbered to correspond therewith.

As illustrated, a neon lamp 13 may be asso-' ing 39, 39a and 39b and maybe positioned directly in front of the switch mechanisms with which theyare associated so that the thread or threads having the imperfectionwill be indicatedat a glance. Such visual indication is desirable in aninstrument wherein a large number of detectors are employed so as toprovide a more prominent visible indication of the thread condition at adistance greater than that at which the chart must be observed.

As illustrated, a switch 14 connected in circuit with the supplyconductors L and L is provided for starting up and deenergizing thesystem. Closure of switch 14 results in energization of themotor-generator set 45 and also in energization of a suitable time delaydevice 15. Device l5 may be of any well known type and is adapted tocontrol the energization of a relay 16 after a suitable time delayperiod, for example, two minutes. This time delay period is provided toensure that the cathodes of valves I9, 15a and lilb are heated beforevoltage is impressed becathode results.

tween the anodes and cathodes thereof. In the operation of valves ofthis type, if anode voltage is impressed between the anode and cathodewhen the latter is cold or before it is up to its operating"temperature, rapid deterioration of the The time delay means andassociated apparatus are employed, therefore, to prevent the occurrenceof such deterioration,

An armature Tl associated with the relay 16 and biased by spring means18 out of engagement with a contact 19 is moved into engagement with thelatter against the opposing force of the spring when the relay isenergized. Armature l1 and contact 19 are connected in the commoncathode circuit of valves l9, Isa, and I91) and close that circuit whenin engagement, but interrupt it when out of engagement. i

The heater filaments of valves [9, [9a and i917 are connected in aparallel circuit with each other and receive energizing current from thetransformer secondary winding 66. Transformer 64 is energizedimmediately upon closure of the line switch 14 so that energizingcurrent fiows at once to the heater filaments. The length of the timedelay period is desirably made long enough to ensure that the cathodesof valves N, Na and l9b will be heated to their operating temperature sothat at the 'end of the time delay period and subsequent closure of thecommon cathode circuit by the relay armature H, the valves will be inoperating condition and no damage will result thereto.

Subject matter disclosed and not claimed in this application is beingclaimed in my copending application Serial No. 118,095 filed Dec. 29,1936.

While in accordance with the provisions of the statutes, I haveillustrated and described the best form of embodiment of my inventionnow known to me, it will be apparent to those skilled in the art thatchanges may be made in the form of the apparatus disclosed withoutdeparting from the spirit of my invention as set forth in the appendedclaims, and that certain features of my invention may sometimes be usedto advantage without a corresponding use of other features. I

Having now described my invention, what I claim as new and desiretosecure by Letters Patent, is: d

1. In apparatus for detecting defective filaments in a' thread,detecting means disposed in the path of the thread and adapted to detectsaid detective filaments, means for relatively.

' moving said thread and said detecting means, a

source of electrical current, relay means, gaseous discharge valve meansunder control of said desaid circuit connection, and recording meanscontrolled by said influencing means.

2. In apparatus for detecting defective filaments in a thread, detectingmeans disposed in the path of the thread and adapted to detect saiddefective filaments, means for relatively. moving said thread and saiddetecting means,

a source of direct current, relay means, gaseous discharge valve meansunder control of said detecting 'means, a circuit connection includingsaid relay means, said gaseous discharge valve means, and said directcurrent source, means under control of said relay means to influencesaid circuit connection, and recording means controlled by saidinfluencing means.

3. In apparatus for detecting defective fila ments in a thread,detecting means disposed in .the path of the thread and adapted todetect said defective filaments, means for relatively moving said threadand said detecting means, a source of direct current, relay means,gaseous discharge valve means under control of said detecting means, acircuit connection including said relay means, said gaseous dischargevalve means, and said direct current source, means under'control of saidrelay means to interrupt said circuit connection, and recording meanscontrolledby said interrupting means.

4. In apparatus for detecting defective filaments in a thread, detectingmeans disposed in the path of the thread, means for relativelymovengaged at one end and rotated by defective filaments in said threadand adapted to engage an electrical contact with its otherend, andflexible spring meansior biasing said arm away from engagement with saidelectrical contact and for damping the oscillation of said arm.

6. In apparatus for detecting detective filaments in a thread a lightarm pivoted intermediate its ends for oscillation and adapted to beengaged at one end and rotated by defective'filaments in said threadand'adapted to engage an electrical contact with its other end, and apair oi. flexible fingers in engagement with said contact arm on eitherside thereof for biasing said arm away from engagement with saidelectrical contact and. for damping the oscillation of said arm. I

' EARL A. p

